1. Field of the Invention
The present invention relates generally to techniques for saving and restoring data, and more particularly the present invention relates to a computer implemented method, system and computer usable program code for improving integrity of data stored on removable storage media such as compact discs and digital versatile/video discs.
2. Description of the Related Art
As data storage densities continue to increase, greater and greater amounts of data can be stored in smaller and smaller containers. For example, today's single-sided, single-layer digital versatile/video disc (DVD) can hold 4.7 gigabytes (GB) of data. In the near future, a single-sided, single-layer HD DVD will hold 15 GB of data, and a comparable Blu-ray Disc will hold 25 GB of data. While not having the same capacity as DVDs, compact discs (CDs) are also useful for saving data due to their relatively low costs.
Use of removable storage media in a multitude of devices is also increasingly common. Digital cameras and camcorders, portable music devices, and electronic games are but a few examples of such use. For non-volatile memory such as compact flash (CF), there is a need to be able to save the current data contents of the non-volatile memory so that the non-volatile memory can be erased and re-used. Storing of such data on a CD or DVD, with the aid of a computer or copying device, is an extremely cost effective way to store or archive such data for subsequent restore or recall.
Still further, removable disc storage media, with its increase in capacity, is now a viable alternative for use in backing up data from another storage device such as a magnetic or optical hard disk drive.
In short, the use of high-density removable media is rapidly increasing. However, with such increased use comes associated risk. Because these media contain so much data, media defects or a natural aging process can result in the loss of significant amounts of data. Such data loss comes from things such as physical damage of the media (breaking, melting, scratching) by careless or improper handling or use of the media, or blocking of the laser light used to access the media (by dirt, paint, ink, glue, or corrosion of the reflecting layer). Certain defects may even exist on raw, never-written or never-used media due to manufacturing defects. Certain techniques are used today to help mitigate such data loss, such as correcting detected errors using algorithmic processes such as error-control and correction (ECC). However, such ECC coding can only handle so much damage before an unrecoverable error occurs.
It would thus be desirable to provide an improved technique for ensuring that data that is copied, backed-up, or migrated to a removable disc such as a CD or DVD can be successfully read or recovered at some future point in time.